The invention relates to an infinitely-variable-speed ultrasonic microdroplet jetting additive manufacturing device and method for multiple materials, and belongs to the field of additive manufacturing. A delta sport substrate device is fixed inside a rack and located below a top plate of the rack. A focused ultrasound system is fixed inside the rack and located above a bottom plate of the rack. A material pool device is located above the focused ultrasound system and fixed to the rack. Feeding devices are fixed to supporting posts of the rack. According to the infinitely-variable-speed ultrasonic microdroplet jetting additive manufacturing device and method for the multiple materials, the focused ultrasound technique and the additive manufacturing technique are combined, the size of jetted liquid drops is not limited by sprayers which are not needed, sprayer blocking is avoided, and the manufacturing cost is lowered; microdroplets are jetted from bottom to top, satellite droplets are prevented, and the printing precision is improved; mixed additive manufacturing for the multiple materials and additive manufacturing for functionally gradient materials can be achieved; and in the printing process, the microdroplet jetting frequency is adjustable, the microdroplet diameter is adjustable, and infinitely-variable-speed microdroplet jetting additive manufacturing can be achieved.